Effects Of GnRH Vaccines Prepared With Two Types Of Novel Adjuvants On The Reproductive Function Of Male Rats

In order to reduce the aggressiveness of male mammalians and improve the meat quality of meat livestock,animals are often castrated at their early agesmale castration to reduce its aggression and improve the quality of meat in the livestock breeding.However,surgical castration is easy to cause the animal infection and stress reaction which is not meet the requirements of animal welfare.In recent years,GnRH vaccine has been gradually used as an alternatives to surgical castrationwith GnRH vaccine with immune castration of animals gradually began to replace traditional surgical castration.Due to GnRH its weak immunogenicity,we improve it's immunogenicity whichGnRH molecule has to be often modify it's molecular,modified or supplemented by combined with immune adjuvants when used as vaccine.This study compared the effects of 2 novel adjuvants on male reproductive function in rats immunized against GnRH 2-mutiple antigen peptide30(GnRH2-MAP),aimed to screen a more effective adjuvant for GnRH vaccine.108 male SD rats(18?20-day-old,35±3g)were assigned into three groups,and then werer administered with normal saline(control),GnRH vaccine prepared with oil adjuvant or water-soluble adjuvant via subcutaneous injection in many sites of the back respectively,followed by two booster doses at 2-week intervals.6 rats from each group every 2 w were collected blood,hypothalamus,pituitary,gonads and accessory gonads tissue from the beginning of first immune till the end of the experiment.The serum testosterone and antibody titers were measured by ELISA,the testes and accessory glands were weighed,and the testis was histologically analyzed mRNA expression levels in the hypothalamus,pituitary,and testes were determined by real-time quantitative PCR.Among the three groups,the oil adjuvant group exhibited the lowest testosterone concentration(P<0.05),the highest antibody titer(P<0.05),and testis atrophy.GnRH mRNA expression in the hypothalamus;GnRH-R,FSH-?,and LH-? expression in the pituitary;and FSH-R,LH-R,and 3?-HSD expression in the testes were significantly lower in this group(P<0.01).Additionally,several other genes showed significant differential expression in the oil adjuvant group than in the other two groups.These data demonstrated that the GnRH2-MAP vaccine emulsified with oil adjuvant is more effective than that administered with water-soluble adjuvant.